5-(2-溴乙基)-2,3-二氢苯并呋喃的制备

Preparation of 5-(2-Bromoethyl)-2,3-dihydrobenzofuran

2,3-二氢苯并呋喃-5-乙酸与氯甲酸乙酯反应得混酐后,再经硼氢化钠还原制得5-羟乙基-2,3-二氢苯并呋喃,在三苯膦作用下经N-溴代琥珀酰亚胺溴代,制得达非那新中间体5-(2-溴乙基)-2,3-二氢苯并呋喃,总收率约83%。

5-（2-Bromoethyl）-2,3-dihydrobenzofuran, the intermediate of darifenacin, was synthesized from 2,3-dihydrobenzofuranyl-5-acetic acid by reaction with ethyl chloroformate and reduction with sodium borohydride to give 5-hydroxyethyl-2,3-dihydrobenzofuran, which was subjected by bromination with N-bromosuccinimide in the presence of triphenylphosphine with an overall yield of about 83 %.